1. Field of the Invention
The present invention provides a method and apparatus for the implantation of an artificial lens implant and more particularly an insertion tool for a flexible intraocular lens.
2. Description of the Prior Art
Intraocular lenses have gained wide acceptance in replacement of the human crystalline lens after a variety of cataract removal procedures. The human crystalline lens is generally recognized to be a transparent structure having a thickness of about 5 millimeters and diameter of about 9 millimeters. The lens is suspended behind the iris by zonular fibers which connect the lens to the ciliary body. A lens capsule surrounds the lens.
Numerous procedures for the removal of cataracts have been developed in which the lens is removed from the eye and replaced by an artificial lens implant. As it is desirable that as small an incision as possible be made in the ocular tissue for both the removal of the lens and the subsequent replacement with an artificial lens, deformable intraocular lenses have recently been developed. Accordingly, the present invention provides an improved method by which a deformable intraocular lens can be inserted into the eye via the small incision.
A number of devices have been developed to facilitate implantation of artificial lenses, for example, U.S. Pat. No. 4,573,998, issued to Mazzocco, describes a number of methods employing such devices. Generally the lens is deformed and constrained to a small volume. Deformable intraocular lenses typically have memory characteristics which enable the lens to be deformed by compressing, rolling, folding or stretching thereof to a diameter of 80% or less of the cross-sectional diameter of the optic part of the lens and yet return to their original configuration full sized and fixed focal length after insertion into the eye. such lenses are often made of silicone or other polymer material.
Various insertion apparatus for use in a deformable lens implantation are known in the prior art. Injection type implantation devices have been used for insertion of the deformable lens into the eye through the small incision. See, for example, FIG. 47 of Mazzocco. In addition, forceps type insertion apparatus have also been used in the prior art, for example, FIGS. 50, 51 and 53 of Mazzocco. Of particular interest to the present invention are the devices and methods calling for forceps-type instruments to grasp the artificial lens and insert it into the eye via a small incision. Some forceps-type devices such as the one described in U.S. Pat. No. 4,198,980, issued to Clark, are designed to interact with the loops and pins of a particular type of intraocular lens design. The forceps described in the Mazzocco patent do not require interaction with loops and pins but rather is capable of grasping any deformable lens. A disadvantage inherent in the above inventions lies in the size of the instrument. The trauma and the chance of additional injury is reduced, if the amount and the size of the instruments inserted into the eye are minimized.